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* [PATCH 01/23] drm/i915: Cache the error string
@ 2018-08-16 21:07 Chris Wilson
  2018-08-16 21:07 ` [PATCH 02/23] drm/i915/execlists: Avoid kicking priority on the current context Chris Wilson
                   ` (25 more replies)
  0 siblings, 26 replies; 28+ messages in thread
From: Chris Wilson @ 2018-08-16 21:07 UTC (permalink / raw)
  To: intel-gfx

Currently, we convert the error state into a string every time we read
from sysfs (and sysfs reads in page size (4KiB) chunks). We do try to
window the string and only capture the portion that is being read, but
that means that we must always convert up to the window to find the
start. For a very large error state bordering on EXEC_OBJECT_CAPTURE
abuse, this is noticeable as it degrades to O(N^2)!

As we do not have a convenient hook for sysfs open(), and we would like
to keep the lazy conversion into a string, do the conversion of the
whole string on the first read and keep the string until the error state
is freed.

v2: Don't double advance simple_read_from_buffer
v3: Due to extreme pain of lack of vrealloc, use a scatterlist
v4: Keep the forward iterator loosely cached

Reported-by: Jason Ekstrand <jason@jlekstrand.net>
Testcase: igt/gem_exec_capture/many*
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
---
 drivers/gpu/drm/i915/i915_debugfs.c   |  32 +-
 drivers/gpu/drm/i915/i915_gpu_error.c | 402 +++++++++++++++-----------
 drivers/gpu/drm/i915/i915_gpu_error.h |  28 +-
 drivers/gpu/drm/i915/i915_sysfs.c     |  27 +-
 4 files changed, 273 insertions(+), 216 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 26b7e5276b15..7620a919e066 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -943,30 +943,28 @@ static int i915_gem_fence_regs_info(struct seq_file *m, void *data)
 static ssize_t gpu_state_read(struct file *file, char __user *ubuf,
 			      size_t count, loff_t *pos)
 {
-	struct i915_gpu_state *error = file->private_data;
-	struct drm_i915_error_state_buf str;
+	struct i915_gpu_state *error;
 	ssize_t ret;
-	loff_t tmp;
+	void *buf;
 
+	error = file->private_data;
 	if (!error)
 		return 0;
 
-	ret = i915_error_state_buf_init(&str, error->i915, count, *pos);
-	if (ret)
-		return ret;
-
-	ret = i915_error_state_to_str(&str, error);
-	if (ret)
-		goto out;
+	/* Bounce buffer required because of kernfs __user API convenience. */
+	buf = kmalloc(count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
 
-	tmp = 0;
-	ret = simple_read_from_buffer(ubuf, count, &tmp, str.buf, str.bytes);
-	if (ret < 0)
-		goto out;
+	ret = i915_gpu_state_copy_to_buffer(error, buf, *pos, count);
+	if (ret > 0) {
+		if (!copy_to_user(ubuf, buf, ret))
+			*pos += ret;
+		else
+			ret = -EFAULT;
+	}
 
-	*pos = str.start + ret;
-out:
-	i915_error_state_buf_release(&str);
+	kfree(buf);
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index f7f2aa71d8d9..5c4e09b6a650 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -28,6 +28,8 @@
  */
 
 #include <generated/utsrelease.h>
+#include <linux/nmi.h>
+#include <linux/scatterlist.h>
 #include <linux/stop_machine.h>
 #include <linux/zlib.h>
 #include <drm/drm_print.h>
@@ -77,112 +79,110 @@ static const char *purgeable_flag(int purgeable)
 	return purgeable ? " purgeable" : "";
 }
 
-static bool __i915_error_ok(struct drm_i915_error_state_buf *e)
+static void __sg_set_buf(struct scatterlist *sg,
+			 void *addr, unsigned int len, loff_t it)
 {
-
-	if (!e->err && WARN(e->bytes > (e->size - 1), "overflow")) {
-		e->err = -ENOSPC;
-		return false;
-	}
-
-	if (e->bytes == e->size - 1 || e->err)
-		return false;
-
-	return true;
+	sg->page_link = (unsigned long)virt_to_page(addr);
+	sg->offset = offset_in_page(addr);
+	sg->length = len;
+	sg->dma_address = it;
 }
 
-static bool __i915_error_seek(struct drm_i915_error_state_buf *e,
-			      unsigned len)
+static bool __i915_error_grow(struct drm_i915_error_state_buf *e, size_t len)
 {
-	if (e->pos + len <= e->start) {
-		e->pos += len;
+	if (!len)
 		return false;
-	}
 
-	/* First vsnprintf needs to fit in its entirety for memmove */
-	if (len >= e->size) {
-		e->err = -EIO;
-		return false;
-	}
+	if (e->bytes + len + 1 > e->size) {
+		if (e->bytes) {
+			__sg_set_buf(e->cur++, e->buf, e->bytes, e->iter);
+			e->iter += e->bytes;
+			e->buf = NULL;
+			e->bytes = 0;
+		}
 
-	return true;
-}
+		if (e->cur == e->end) {
+			struct scatterlist *sgl;
 
-static void __i915_error_advance(struct drm_i915_error_state_buf *e,
-				 unsigned len)
-{
-	/* If this is first printf in this window, adjust it so that
-	 * start position matches start of the buffer
-	 */
+			sgl = (typeof(sgl))__get_free_page(GFP_KERNEL);
+			if (!sgl) {
+				e->err = -ENOMEM;
+				return false;
+			}
 
-	if (e->pos < e->start) {
-		const size_t off = e->start - e->pos;
+			if (e->cur) {
+				e->cur->offset = 0;
+				e->cur->length = 0;
+				e->cur->page_link =
+					(unsigned long)sgl | SG_CHAIN;
+			} else {
+				e->sgl = sgl;
+			}
 
-		/* Should not happen but be paranoid */
-		if (off > len || e->bytes) {
-			e->err = -EIO;
-			return;
+			e->cur = sgl;
+			e->end = sgl + SG_MAX_SINGLE_ALLOC - 1;
 		}
 
-		memmove(e->buf, e->buf + off, len - off);
-		e->bytes = len - off;
-		e->pos = e->start;
-		return;
+		e->size = ALIGN(len + 1, SZ_64K);
+		e->buf = kmalloc(e->size,
+				 GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
+		if (!e->buf) {
+			e->size = PAGE_ALIGN(len + 1);
+			e->buf = kmalloc(e->size, GFP_KERNEL);
+		}
+		if (!e->buf) {
+			e->err = -ENOMEM;
+			return false;
+		}
 	}
 
-	e->bytes += len;
-	e->pos += len;
+	return true;
 }
 
 __printf(2, 0)
 static void i915_error_vprintf(struct drm_i915_error_state_buf *e,
-			       const char *f, va_list args)
+			       const char *fmt, va_list args)
 {
-	unsigned len;
+	va_list ap;
+	int len;
 
-	if (!__i915_error_ok(e))
+	if (e->err)
 		return;
 
-	/* Seek the first printf which is hits start position */
-	if (e->pos < e->start) {
-		va_list tmp;
-
-		va_copy(tmp, args);
-		len = vsnprintf(NULL, 0, f, tmp);
-		va_end(tmp);
-
-		if (!__i915_error_seek(e, len))
-			return;
+	va_copy(ap, args);
+	len = vsnprintf(NULL, 0, fmt, ap);
+	va_end(ap);
+	if (len <= 0) {
+		e->err = len;
+		return;
 	}
 
-	len = vsnprintf(e->buf + e->bytes, e->size - e->bytes, f, args);
-	if (len >= e->size - e->bytes)
-		len = e->size - e->bytes - 1;
+	if (!__i915_error_grow(e, len))
+		return;
 
-	__i915_error_advance(e, len);
+	GEM_BUG_ON(e->bytes >= e->size);
+	len = vscnprintf(e->buf + e->bytes, e->size - e->bytes, fmt, args);
+	if (len < 0) {
+		e->err = len;
+		return;
+	}
+	e->bytes += len;
 }
 
-static void i915_error_puts(struct drm_i915_error_state_buf *e,
-			    const char *str)
+static void i915_error_puts(struct drm_i915_error_state_buf *e, const char *str)
 {
 	unsigned len;
 
-	if (!__i915_error_ok(e))
+	if (e->err || !str)
 		return;
 
 	len = strlen(str);
+	if (!__i915_error_grow(e, len))
+		return;
 
-	/* Seek the first printf which is hits start position */
-	if (e->pos < e->start) {
-		if (!__i915_error_seek(e, len))
-			return;
-	}
-
-	if (len >= e->size - e->bytes)
-		len = e->size - e->bytes - 1;
+	GEM_BUG_ON(e->bytes + len > e->size);
 	memcpy(e->buf + e->bytes, str, len);
-
-	__i915_error_advance(e, len);
+	e->bytes += len;
 }
 
 #define err_printf(e, ...) i915_error_printf(e, __VA_ARGS__)
@@ -259,6 +259,8 @@ static int compress_page(struct compress *c,
 
 		if (zlib_deflate(zstream, Z_SYNC_FLUSH) != Z_OK)
 			return -EIO;
+
+		touch_nmi_watchdog();
 	} while (zstream->avail_in);
 
 	/* Fallback to uncompressed if we increase size? */
@@ -597,33 +599,50 @@ static void err_print_uc(struct drm_i915_error_state_buf *m,
 	print_error_obj(m, NULL, "GuC log buffer", error_uc->guc_log);
 }
 
-int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
-			    const struct i915_gpu_state *error)
+static void err_free_sgl(struct scatterlist *sgl)
 {
-	struct drm_i915_private *dev_priv = m->i915;
+	while (sgl) {
+		struct scatterlist *sg;
+
+		for (sg = sgl; !sg_is_chain(sg); sg++) {
+			kfree(sg_virt(sg));
+			if (sg_is_last(sg))
+				break;
+		}
+
+		sg = sg_is_last(sg) ? NULL : sg_chain_ptr(sg);
+		free_page((unsigned long)sgl);
+		sgl = sg;
+	}
+}
+
+static int err_print_to_sgl(struct i915_gpu_state *error)
+{
+	struct drm_i915_error_state_buf m;
 	struct drm_i915_error_object *obj;
 	struct timespec64 ts;
 	int i, j;
 
-	if (!error) {
-		err_printf(m, "No error state collected\n");
+	if (READ_ONCE(error->sgl))
 		return 0;
-	}
+
+	memset(&m, 0, sizeof(m));
+	m.i915 = error->i915;
 
 	if (*error->error_msg)
-		err_printf(m, "%s\n", error->error_msg);
-	err_printf(m, "Kernel: " UTS_RELEASE "\n");
+		err_printf(&m, "%s\n", error->error_msg);
+	err_printf(&m, "Kernel: " UTS_RELEASE "\n");
 	ts = ktime_to_timespec64(error->time);
-	err_printf(m, "Time: %lld s %ld us\n",
+	err_printf(&m, "Time: %lld s %ld us\n",
 		   (s64)ts.tv_sec, ts.tv_nsec / NSEC_PER_USEC);
 	ts = ktime_to_timespec64(error->boottime);
-	err_printf(m, "Boottime: %lld s %ld us\n",
+	err_printf(&m, "Boottime: %lld s %ld us\n",
 		   (s64)ts.tv_sec, ts.tv_nsec / NSEC_PER_USEC);
 	ts = ktime_to_timespec64(error->uptime);
-	err_printf(m, "Uptime: %lld s %ld us\n",
+	err_printf(&m, "Uptime: %lld s %ld us\n",
 		   (s64)ts.tv_sec, ts.tv_nsec / NSEC_PER_USEC);
-	err_printf(m, "Epoch: %lu jiffies (%u HZ)\n", error->epoch, HZ);
-	err_printf(m, "Capture: %lu jiffies; %d ms ago, %d ms after epoch\n",
+	err_printf(&m, "Epoch: %lu jiffies (%u HZ)\n", error->epoch, HZ);
+	err_printf(&m, "Capture: %lu jiffies; %d ms ago, %d ms after epoch\n",
 		   error->capture,
 		   jiffies_to_msecs(jiffies - error->capture),
 		   jiffies_to_msecs(error->capture - error->epoch));
@@ -631,63 +650,63 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
 	for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
 		if (error->engine[i].hangcheck_stalled &&
 		    error->engine[i].context.pid) {
-			err_printf(m, "Active process (on ring %s): %s [%d], score %d%s\n",
-				   engine_name(m->i915, i),
+			err_printf(&m, "Active process (on ring %s): %s [%d], score %d%s\n",
+				   engine_name(m.i915, i),
 				   error->engine[i].context.comm,
 				   error->engine[i].context.pid,
 				   error->engine[i].context.ban_score,
 				   bannable(&error->engine[i].context));
 		}
 	}
-	err_printf(m, "Reset count: %u\n", error->reset_count);
-	err_printf(m, "Suspend count: %u\n", error->suspend_count);
-	err_printf(m, "Platform: %s\n", intel_platform_name(error->device_info.platform));
-	err_print_pciid(m, error->i915);
+	err_printf(&m, "Reset count: %u\n", error->reset_count);
+	err_printf(&m, "Suspend count: %u\n", error->suspend_count);
+	err_printf(&m, "Platform: %s\n", intel_platform_name(error->device_info.platform));
+	err_print_pciid(&m, m.i915);
 
-	err_printf(m, "IOMMU enabled?: %d\n", error->iommu);
+	err_printf(&m, "IOMMU enabled?: %d\n", error->iommu);
 
-	if (HAS_CSR(dev_priv)) {
-		struct intel_csr *csr = &dev_priv->csr;
+	if (HAS_CSR(m.i915)) {
+		struct intel_csr *csr = &m.i915->csr;
 
-		err_printf(m, "DMC loaded: %s\n",
+		err_printf(&m, "DMC loaded: %s\n",
 			   yesno(csr->dmc_payload != NULL));
-		err_printf(m, "DMC fw version: %d.%d\n",
+		err_printf(&m, "DMC fw version: %d.%d\n",
 			   CSR_VERSION_MAJOR(csr->version),
 			   CSR_VERSION_MINOR(csr->version));
 	}
 
-	err_printf(m, "GT awake: %s\n", yesno(error->awake));
-	err_printf(m, "RPM wakelock: %s\n", yesno(error->wakelock));
-	err_printf(m, "PM suspended: %s\n", yesno(error->suspended));
-	err_printf(m, "EIR: 0x%08x\n", error->eir);
-	err_printf(m, "IER: 0x%08x\n", error->ier);
+	err_printf(&m, "GT awake: %s\n", yesno(error->awake));
+	err_printf(&m, "RPM wakelock: %s\n", yesno(error->wakelock));
+	err_printf(&m, "PM suspended: %s\n", yesno(error->suspended));
+	err_printf(&m, "EIR: 0x%08x\n", error->eir);
+	err_printf(&m, "IER: 0x%08x\n", error->ier);
 	for (i = 0; i < error->ngtier; i++)
-		err_printf(m, "GTIER[%d]: 0x%08x\n", i, error->gtier[i]);
-	err_printf(m, "PGTBL_ER: 0x%08x\n", error->pgtbl_er);
-	err_printf(m, "FORCEWAKE: 0x%08x\n", error->forcewake);
-	err_printf(m, "DERRMR: 0x%08x\n", error->derrmr);
-	err_printf(m, "CCID: 0x%08x\n", error->ccid);
-	err_printf(m, "Missed interrupts: 0x%08lx\n", dev_priv->gpu_error.missed_irq_rings);
+		err_printf(&m, "GTIER[%d]: 0x%08x\n", i, error->gtier[i]);
+	err_printf(&m, "PGTBL_ER: 0x%08x\n", error->pgtbl_er);
+	err_printf(&m, "FORCEWAKE: 0x%08x\n", error->forcewake);
+	err_printf(&m, "DERRMR: 0x%08x\n", error->derrmr);
+	err_printf(&m, "CCID: 0x%08x\n", error->ccid);
+	err_printf(&m, "Missed interrupts: 0x%08lx\n", m.i915->gpu_error.missed_irq_rings);
 
 	for (i = 0; i < error->nfence; i++)
-		err_printf(m, "  fence[%d] = %08llx\n", i, error->fence[i]);
+		err_printf(&m, "  fence[%d] = %08llx\n", i, error->fence[i]);
 
-	if (INTEL_GEN(dev_priv) >= 6) {
-		err_printf(m, "ERROR: 0x%08x\n", error->error);
+	if (INTEL_GEN(m.i915) >= 6) {
+		err_printf(&m, "ERROR: 0x%08x\n", error->error);
 
-		if (INTEL_GEN(dev_priv) >= 8)
-			err_printf(m, "FAULT_TLB_DATA: 0x%08x 0x%08x\n",
+		if (INTEL_GEN(m.i915) >= 8)
+			err_printf(&m, "FAULT_TLB_DATA: 0x%08x 0x%08x\n",
 				   error->fault_data1, error->fault_data0);
 
-		err_printf(m, "DONE_REG: 0x%08x\n", error->done_reg);
+		err_printf(&m, "DONE_REG: 0x%08x\n", error->done_reg);
 	}
 
-	if (IS_GEN7(dev_priv))
-		err_printf(m, "ERR_INT: 0x%08x\n", error->err_int);
+	if (IS_GEN7(m.i915))
+		err_printf(&m, "ERR_INT: 0x%08x\n", error->err_int);
 
 	for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
 		if (error->engine[i].engine_id != -1)
-			error_print_engine(m, &error->engine[i], error->epoch);
+			error_print_engine(&m, &error->engine[i], error->epoch);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(error->active_vm); i++) {
@@ -704,16 +723,16 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
 
 			len += scnprintf(buf + len, sizeof(buf), "%s%s",
 					 first ? "" : ", ",
-					 dev_priv->engine[j]->name);
+					 m.i915->engine[j]->name);
 			first = 0;
 		}
 		scnprintf(buf + len, sizeof(buf), ")");
-		print_error_buffers(m, buf,
+		print_error_buffers(&m, buf,
 				    error->active_bo[i],
 				    error->active_bo_count[i]);
 	}
 
-	print_error_buffers(m, "Pinned (global)",
+	print_error_buffers(&m, "Pinned (global)",
 			    error->pinned_bo,
 			    error->pinned_bo_count);
 
@@ -722,115 +741,163 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
 
 		obj = ee->batchbuffer;
 		if (obj) {
-			err_puts(m, dev_priv->engine[i]->name);
+			err_puts(&m, m.i915->engine[i]->name);
 			if (ee->context.pid)
-				err_printf(m, " (submitted by %s [%d], ctx %d [%d], score %d%s)",
+				err_printf(&m, " (submitted by %s [%d], ctx %d [%d], score %d%s)",
 					   ee->context.comm,
 					   ee->context.pid,
 					   ee->context.handle,
 					   ee->context.hw_id,
 					   ee->context.ban_score,
 					   bannable(&ee->context));
-			err_printf(m, " --- gtt_offset = 0x%08x %08x\n",
+			err_printf(&m, " --- gtt_offset = 0x%08x %08x\n",
 				   upper_32_bits(obj->gtt_offset),
 				   lower_32_bits(obj->gtt_offset));
-			print_error_obj(m, dev_priv->engine[i], NULL, obj);
+			print_error_obj(&m, m.i915->engine[i], NULL, obj);
 		}
 
 		for (j = 0; j < ee->user_bo_count; j++)
-			print_error_obj(m, dev_priv->engine[i],
+			print_error_obj(&m, m.i915->engine[i],
 					"user", ee->user_bo[j]);
 
 		if (ee->num_requests) {
-			err_printf(m, "%s --- %d requests\n",
-				   dev_priv->engine[i]->name,
+			err_printf(&m, "%s --- %d requests\n",
+				   m.i915->engine[i]->name,
 				   ee->num_requests);
 			for (j = 0; j < ee->num_requests; j++)
-				error_print_request(m, " ",
+				error_print_request(&m, " ",
 						    &ee->requests[j],
 						    error->epoch);
 		}
 
 		if (IS_ERR(ee->waiters)) {
-			err_printf(m, "%s --- ? waiters [unable to acquire spinlock]\n",
-				   dev_priv->engine[i]->name);
+			err_printf(&m, "%s --- ? waiters [unable to acquire spinlock]\n",
+				   m.i915->engine[i]->name);
 		} else if (ee->num_waiters) {
-			err_printf(m, "%s --- %d waiters\n",
-				   dev_priv->engine[i]->name,
+			err_printf(&m, "%s --- %d waiters\n",
+				   m.i915->engine[i]->name,
 				   ee->num_waiters);
 			for (j = 0; j < ee->num_waiters; j++) {
-				err_printf(m, " seqno 0x%08x for %s [%d]\n",
+				err_printf(&m, " seqno 0x%08x for %s [%d]\n",
 					   ee->waiters[j].seqno,
 					   ee->waiters[j].comm,
 					   ee->waiters[j].pid);
 			}
 		}
 
-		print_error_obj(m, dev_priv->engine[i],
+		print_error_obj(&m, m.i915->engine[i],
 				"ringbuffer", ee->ringbuffer);
 
-		print_error_obj(m, dev_priv->engine[i],
+		print_error_obj(&m, m.i915->engine[i],
 				"HW Status", ee->hws_page);
 
-		print_error_obj(m, dev_priv->engine[i],
+		print_error_obj(&m, m.i915->engine[i],
 				"HW context", ee->ctx);
 
-		print_error_obj(m, dev_priv->engine[i],
+		print_error_obj(&m, m.i915->engine[i],
 				"WA context", ee->wa_ctx);
 
-		print_error_obj(m, dev_priv->engine[i],
+		print_error_obj(&m, m.i915->engine[i],
 				"WA batchbuffer", ee->wa_batchbuffer);
 
-		print_error_obj(m, dev_priv->engine[i],
+		print_error_obj(&m, m.i915->engine[i],
 				"NULL context", ee->default_state);
 	}
 
 	if (error->overlay)
-		intel_overlay_print_error_state(m, error->overlay);
+		intel_overlay_print_error_state(&m, error->overlay);
 
 	if (error->display)
-		intel_display_print_error_state(m, error->display);
+		intel_display_print_error_state(&m, error->display);
 
-	err_print_capabilities(m, &error->device_info, &error->driver_caps);
-	err_print_params(m, &error->params);
-	err_print_uc(m, &error->uc);
+	err_print_capabilities(&m, &error->device_info, &error->driver_caps);
+	err_print_params(&m, &error->params);
+	err_print_uc(&m, &error->uc);
 
-	if (m->bytes == 0 && m->err)
-		return m->err;
+	if (m.buf) {
+		__sg_set_buf(m.cur++, m.buf, m.bytes, m.iter);
+		m.bytes = 0;
+		m.buf = 0;
+	}
+	if (m.cur) {
+		GEM_BUG_ON(m.end < m.cur);
+		sg_mark_end(m.cur - 1);
+	}
+	GEM_BUG_ON(m.sgl && !m.cur);
+
+	if (m.err) {
+		err_free_sgl(m.sgl);
+		return m.err;
+	}
+
+	if (cmpxchg(&error->sgl, NULL, m.sgl))
+		err_free_sgl(m.sgl);
 
 	return 0;
 }
 
-int i915_error_state_buf_init(struct drm_i915_error_state_buf *ebuf,
-			      struct drm_i915_private *i915,
-			      size_t count, loff_t pos)
+ssize_t i915_gpu_state_copy_to_buffer(struct i915_gpu_state *error,
+				      char *buf, loff_t off, size_t rem)
 {
-	memset(ebuf, 0, sizeof(*ebuf));
-	ebuf->i915 = i915;
+	struct scatterlist *sg;
+	size_t count;
+	loff_t pos;
+	int err;
 
-	/* We need to have enough room to store any i915_error_state printf
-	 * so that we can move it to start position.
-	 */
-	ebuf->size = count + 1 > PAGE_SIZE ? count + 1 : PAGE_SIZE;
-	ebuf->buf = kmalloc(ebuf->size,
-				GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
+	if (!error || !rem)
+		return 0;
 
-	if (ebuf->buf == NULL) {
-		ebuf->size = PAGE_SIZE;
-		ebuf->buf = kmalloc(ebuf->size, GFP_KERNEL);
-	}
+	err = err_print_to_sgl(error);
+	if (err)
+		return err;
 
-	if (ebuf->buf == NULL) {
-		ebuf->size = 128;
-		ebuf->buf = kmalloc(ebuf->size, GFP_KERNEL);
-	}
+	sg = READ_ONCE(error->fit);
+	if (!sg || off < sg->dma_address)
+		sg = error->sgl;
+	if (!sg)
+		return 0;
 
-	if (ebuf->buf == NULL)
-		return -ENOMEM;
+	pos = sg->dma_address;
+	count = 0;
+	do {
+		size_t len, start;
 
-	ebuf->start = pos;
+		if (sg_is_chain(sg)) {
+			sg = sg_chain_ptr(sg);
+			GEM_BUG_ON(sg_is_chain(sg));
+		}
 
-	return 0;
+		len = sg->length;
+		if (pos + len <= off) {
+			pos += len;
+			continue;
+		}
+
+		start = sg->offset;
+		if (pos < off) {
+			GEM_BUG_ON(off - pos > len);
+			len -= off - pos;
+			start += off - pos;
+			pos = off;
+		}
+
+		len = min(len, rem);
+		GEM_BUG_ON(!len || len > sg->length);
+
+		memcpy(buf, page_address(sg_page(sg)) + start, len);
+
+		count += len;
+		pos += len;
+
+		buf += len;
+		rem -= len;
+		if (!rem) {
+			WRITE_ONCE(error->fit, sg);
+			break;
+		}
+	} while (!sg_is_last(sg++));
+
+	return count;
 }
 
 static void i915_error_object_free(struct drm_i915_error_object *obj)
@@ -903,6 +970,7 @@ void __i915_gpu_state_free(struct kref *error_ref)
 	cleanup_params(error);
 	cleanup_uc_state(error);
 
+	err_free_sgl(error->sgl);
 	kfree(error);
 }
 
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
index f893a4e8b783..1c1bc0c23468 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.h
+++ b/drivers/gpu/drm/i915/i915_gpu_error.h
@@ -191,6 +191,8 @@ struct i915_gpu_state {
 	} *active_bo[I915_NUM_ENGINES], *pinned_bo;
 	u32 active_bo_count[I915_NUM_ENGINES], pinned_bo_count;
 	struct i915_address_space *active_vm[I915_NUM_ENGINES];
+
+	struct scatterlist *sgl, *fit;
 };
 
 struct i915_gpu_error {
@@ -297,29 +299,20 @@ struct i915_gpu_error {
 
 struct drm_i915_error_state_buf {
 	struct drm_i915_private *i915;
-	unsigned int bytes;
-	unsigned int size;
+	struct scatterlist *sgl, *cur, *end;
+
+	char *buf;
+	size_t bytes;
+	size_t size;
+	loff_t iter;
+
 	int err;
-	u8 *buf;
-	loff_t start;
-	loff_t pos;
 };
 
 #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
 
 __printf(2, 3)
 void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...);
-int i915_error_state_to_str(struct drm_i915_error_state_buf *estr,
-			    const struct i915_gpu_state *gpu);
-int i915_error_state_buf_init(struct drm_i915_error_state_buf *eb,
-			      struct drm_i915_private *i915,
-			      size_t count, loff_t pos);
-
-static inline void
-i915_error_state_buf_release(struct drm_i915_error_state_buf *eb)
-{
-	kfree(eb->buf);
-}
 
 struct i915_gpu_state *i915_capture_gpu_state(struct drm_i915_private *i915);
 void i915_capture_error_state(struct drm_i915_private *dev_priv,
@@ -333,6 +326,9 @@ i915_gpu_state_get(struct i915_gpu_state *gpu)
 	return gpu;
 }
 
+ssize_t i915_gpu_state_copy_to_buffer(struct i915_gpu_state *error,
+				      char *buf, loff_t offset, size_t count);
+
 void __i915_gpu_state_free(struct kref *kref);
 static inline void i915_gpu_state_put(struct i915_gpu_state *gpu)
 {
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index e5e6f6bb2b05..ae63a7d0f51d 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -516,26 +516,21 @@ static ssize_t error_state_read(struct file *filp, struct kobject *kobj,
 {
 
 	struct device *kdev = kobj_to_dev(kobj);
-	struct drm_i915_private *dev_priv = kdev_minor_to_i915(kdev);
-	struct drm_i915_error_state_buf error_str;
+	struct drm_i915_private *i915 = kdev_minor_to_i915(kdev);
 	struct i915_gpu_state *gpu;
 	ssize_t ret;
 
-	ret = i915_error_state_buf_init(&error_str, dev_priv, count, off);
-	if (ret)
-		return ret;
-
-	gpu = i915_first_error_state(dev_priv);
-	ret = i915_error_state_to_str(&error_str, gpu);
-	if (ret)
-		goto out;
-
-	ret = count < error_str.bytes ? count : error_str.bytes;
-	memcpy(buf, error_str.buf, ret);
+	gpu = i915_first_error_state(i915);
+	if (gpu) {
+		ret = i915_gpu_state_copy_to_buffer(gpu, buf, off, count);
+		i915_gpu_state_put(gpu);
+	} else {
+		const char *str = "No error state collected\n";
+		size_t len = strlen(str);
 
-out:
-	i915_gpu_state_put(gpu);
-	i915_error_state_buf_release(&error_str);
+		ret = min_t(size_t, count, len - off);
+		memcpy(buf, str + off, ret);
+	}
 
 	return ret;
 }
-- 
2.18.0

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

^ permalink raw reply related	[flat|nested] 28+ messages in thread
* [PATCH 01/23] drm/i915: Reduce context HW ID lifetime
@ 2018-09-04 21:57 Chris Wilson
  2018-09-04 21:57 ` [PATCH 02/23] drm/i915/execlists: Avoid kicking priority on the current context Chris Wilson
  0 siblings, 1 reply; 28+ messages in thread
From: Chris Wilson @ 2018-09-04 21:57 UTC (permalink / raw)
  To: intel-gfx; +Cc: Mika Kuoppala

Future gen reduce the number of bits we will have available to
differentiate between contexts, so reduce the lifetime of the ID
assignment from that of the context to its current active cycle (i.e.
only while it is pinned for use by the HW, will it have a constant ID).
This means that instead of a max of 2k allocated contexts (worst case
before fun with bit twiddling), we instead have a limit of 2k in flight
contexts (minus a few that have been pinned by the kernel or by perf).

To reduce the number of contexts id we require, we allocate a context id
on first and mark it as pinned for as long as the GEM context itself is,
that is we keep it pinned it while active on each engine. If we exhaust
our context id space, then we try to reclaim an id from an idle context.
In the extreme case where all context ids are pinned by active contexts,
we force the system to idle in order to recover ids.

We cannot reduce the scope of an HW-ID to an engine (allowing the same
gem_context to have different ids on each engine) as in the future we
will need to preassign an id before we know which engine the
context is being executed on.

v2: Improved commentary (Tvrtko) [I tried at least]

References: https://bugs.freedesktop.org/show_bug.cgi?id=107788
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c           |   5 +-
 drivers/gpu/drm/i915/i915_drv.h               |   2 +
 drivers/gpu/drm/i915/i915_gem_context.c       | 222 +++++++++++++-----
 drivers/gpu/drm/i915/i915_gem_context.h       |  23 ++
 drivers/gpu/drm/i915/intel_lrc.c              |   8 +
 drivers/gpu/drm/i915/selftests/mock_context.c |  11 +-
 6 files changed, 201 insertions(+), 70 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 4ad0e2ed8610..1f7051e97afb 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1953,7 +1953,10 @@ static int i915_context_status(struct seq_file *m, void *unused)
 		return ret;
 
 	list_for_each_entry(ctx, &dev_priv->contexts.list, link) {
-		seq_printf(m, "HW context %u ", ctx->hw_id);
+		seq_puts(m, "HW context ");
+		if (!list_empty(&ctx->hw_id_link))
+			seq_printf(m, "%x [pin %u]", ctx->hw_id,
+				   atomic_read(&ctx->hw_id_pin_count));
 		if (ctx->pid) {
 			struct task_struct *task;
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5a4da5b723fd..767615ecdea5 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1861,6 +1861,7 @@ struct drm_i915_private {
 	struct mutex av_mutex;
 
 	struct {
+		struct mutex mutex;
 		struct list_head list;
 		struct llist_head free_list;
 		struct work_struct free_work;
@@ -1873,6 +1874,7 @@ struct drm_i915_private {
 #define MAX_CONTEXT_HW_ID (1<<21) /* exclusive */
 #define MAX_GUC_CONTEXT_HW_ID (1 << 20) /* exclusive */
 #define GEN11_MAX_CONTEXT_HW_ID (1<<11) /* exclusive */
+		struct list_head hw_id_list;
 	} contexts;
 
 	u32 fdi_rx_config;
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index f15a039772db..747b8170a15a 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -115,6 +115,95 @@ static void lut_close(struct i915_gem_context *ctx)
 	rcu_read_unlock();
 }
 
+static inline int new_hw_id(struct drm_i915_private *i915, gfp_t gfp)
+{
+	unsigned int max;
+
+	lockdep_assert_held(&i915->contexts.mutex);
+
+	if (INTEL_GEN(i915) >= 11)
+		max = GEN11_MAX_CONTEXT_HW_ID;
+	else if (USES_GUC_SUBMISSION(i915))
+		/*
+		 * When using GuC in proxy submission, GuC consumes the
+		 * highest bit in the context id to indicate proxy submission.
+		 */
+		max = MAX_GUC_CONTEXT_HW_ID;
+	else
+		max = MAX_CONTEXT_HW_ID;
+
+	return ida_simple_get(&i915->contexts.hw_ida, 0, max, gfp);
+}
+
+static int steal_hw_id(struct drm_i915_private *i915)
+{
+	struct i915_gem_context *ctx, *cn;
+	LIST_HEAD(pinned);
+	int id = -ENOSPC;
+
+	lockdep_assert_held(&i915->contexts.mutex);
+
+	list_for_each_entry_safe(ctx, cn,
+				 &i915->contexts.hw_id_list, hw_id_link) {
+		if (atomic_read(&ctx->hw_id_pin_count)) {
+			list_move_tail(&ctx->hw_id_link, &pinned);
+			continue;
+		}
+
+		GEM_BUG_ON(!ctx->hw_id); /* perma-pinned kernel context */
+		list_del_init(&ctx->hw_id_link);
+		id = ctx->hw_id;
+		break;
+	}
+
+	/*
+	 * Remember how far we got up on the last repossesion scan, so the
+	 * list is kept in a "least recently scanned" order.
+	 */
+	list_splice_tail(&pinned, &i915->contexts.hw_id_list);
+	return id;
+}
+
+static int assign_hw_id(struct drm_i915_private *i915, unsigned int *out)
+{
+	int ret;
+
+	lockdep_assert_held(&i915->contexts.mutex);
+
+	/*
+	 * We prefer to steal/stall ourselves and our users over that of the
+	 * entire system. That may be a little unfair to our users, and
+	 * even hurt high priority clients. The choice is whether to oomkill
+	 * something else, or steal a context id.
+	 */
+	ret = new_hw_id(i915, GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+	if (unlikely(ret < 0)) {
+		ret = steal_hw_id(i915);
+		if (ret < 0) /* once again for the correct errno code */
+			ret = new_hw_id(i915, GFP_KERNEL);
+		if (ret < 0)
+			return ret;
+	}
+
+	*out = ret;
+	return 0;
+}
+
+static void release_hw_id(struct i915_gem_context *ctx)
+{
+	struct drm_i915_private *i915 = ctx->i915;
+
+	if (list_empty(&ctx->hw_id_link))
+		return;
+
+	mutex_lock(&i915->contexts.mutex);
+	if (!list_empty(&ctx->hw_id_link)) {
+		ida_simple_remove(&i915->contexts.hw_ida, ctx->hw_id);
+		list_del_init(&ctx->hw_id_link);
+	}
+	mutex_unlock(&i915->contexts.mutex);
+}
+
 static void i915_gem_context_free(struct i915_gem_context *ctx)
 {
 	unsigned int n;
@@ -122,6 +211,7 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
 	GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
 
+	release_hw_id(ctx);
 	i915_ppgtt_put(ctx->ppgtt);
 
 	for (n = 0; n < ARRAY_SIZE(ctx->__engine); n++) {
@@ -136,7 +226,6 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 
 	list_del(&ctx->link);
 
-	ida_simple_remove(&ctx->i915->contexts.hw_ida, ctx->hw_id);
 	kfree_rcu(ctx, rcu);
 }
 
@@ -190,6 +279,12 @@ static void context_close(struct i915_gem_context *ctx)
 {
 	i915_gem_context_set_closed(ctx);
 
+	/*
+	 * This context will never again be assinged to HW, so we can
+	 * reuse its ID for the next context.
+	 */
+	release_hw_id(ctx);
+
 	/*
 	 * The LUT uses the VMA as a backpointer to unref the object,
 	 * so we need to clear the LUT before we close all the VMA (inside
@@ -203,43 +298,6 @@ static void context_close(struct i915_gem_context *ctx)
 	i915_gem_context_put(ctx);
 }
 
-static int assign_hw_id(struct drm_i915_private *dev_priv, unsigned *out)
-{
-	int ret;
-	unsigned int max;
-
-	if (INTEL_GEN(dev_priv) >= 11) {
-		max = GEN11_MAX_CONTEXT_HW_ID;
-	} else {
-		/*
-		 * When using GuC in proxy submission, GuC consumes the
-		 * highest bit in the context id to indicate proxy submission.
-		 */
-		if (USES_GUC_SUBMISSION(dev_priv))
-			max = MAX_GUC_CONTEXT_HW_ID;
-		else
-			max = MAX_CONTEXT_HW_ID;
-	}
-
-
-	ret = ida_simple_get(&dev_priv->contexts.hw_ida,
-			     0, max, GFP_KERNEL);
-	if (ret < 0) {
-		/* Contexts are only released when no longer active.
-		 * Flush any pending retires to hopefully release some
-		 * stale contexts and try again.
-		 */
-		i915_retire_requests(dev_priv);
-		ret = ida_simple_get(&dev_priv->contexts.hw_ida,
-				     0, max, GFP_KERNEL);
-		if (ret < 0)
-			return ret;
-	}
-
-	*out = ret;
-	return 0;
-}
-
 static u32 default_desc_template(const struct drm_i915_private *i915,
 				 const struct i915_hw_ppgtt *ppgtt)
 {
@@ -276,12 +334,6 @@ __create_hw_context(struct drm_i915_private *dev_priv,
 	if (ctx == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	ret = assign_hw_id(dev_priv, &ctx->hw_id);
-	if (ret) {
-		kfree(ctx);
-		return ERR_PTR(ret);
-	}
-
 	kref_init(&ctx->ref);
 	list_add_tail(&ctx->link, &dev_priv->contexts.list);
 	ctx->i915 = dev_priv;
@@ -295,6 +347,7 @@ __create_hw_context(struct drm_i915_private *dev_priv,
 
 	INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
 	INIT_LIST_HEAD(&ctx->handles_list);
+	INIT_LIST_HEAD(&ctx->hw_id_link);
 
 	/* Default context will never have a file_priv */
 	ret = DEFAULT_CONTEXT_HANDLE;
@@ -421,15 +474,35 @@ i915_gem_context_create_gvt(struct drm_device *dev)
 	return ctx;
 }
 
+static void
+destroy_kernel_context(struct i915_gem_context **ctxp)
+{
+	struct i915_gem_context *ctx;
+
+	/* Keep the context ref so that we can free it immediately ourselves */
+	ctx = i915_gem_context_get(fetch_and_zero(ctxp));
+	GEM_BUG_ON(!i915_gem_context_is_kernel(ctx));
+
+	context_close(ctx);
+	i915_gem_context_free(ctx);
+}
+
 struct i915_gem_context *
 i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio)
 {
 	struct i915_gem_context *ctx;
+	int err;
 
 	ctx = i915_gem_create_context(i915, NULL);
 	if (IS_ERR(ctx))
 		return ctx;
 
+	err = i915_gem_context_pin_hw_id(ctx);
+	if (err) {
+		destroy_kernel_context(&ctx);
+		return ERR_PTR(err);
+	}
+
 	i915_gem_context_clear_bannable(ctx);
 	ctx->sched.priority = prio;
 	ctx->ring_size = PAGE_SIZE;
@@ -439,17 +512,19 @@ i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio)
 	return ctx;
 }
 
-static void
-destroy_kernel_context(struct i915_gem_context **ctxp)
+static void init_contexts(struct drm_i915_private *i915)
 {
-	struct i915_gem_context *ctx;
+	mutex_init(&i915->contexts.mutex);
+	INIT_LIST_HEAD(&i915->contexts.list);
 
-	/* Keep the context ref so that we can free it immediately ourselves */
-	ctx = i915_gem_context_get(fetch_and_zero(ctxp));
-	GEM_BUG_ON(!i915_gem_context_is_kernel(ctx));
+	/* Using the simple ida interface, the max is limited by sizeof(int) */
+	BUILD_BUG_ON(MAX_CONTEXT_HW_ID > INT_MAX);
+	BUILD_BUG_ON(GEN11_MAX_CONTEXT_HW_ID > INT_MAX);
+	ida_init(&i915->contexts.hw_ida);
+	INIT_LIST_HEAD(&i915->contexts.hw_id_list);
 
-	context_close(ctx);
-	i915_gem_context_free(ctx);
+	INIT_WORK(&i915->contexts.free_work, contexts_free_worker);
+	init_llist_head(&i915->contexts.free_list);
 }
 
 static bool needs_preempt_context(struct drm_i915_private *i915)
@@ -470,14 +545,7 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 	if (ret)
 		return ret;
 
-	INIT_LIST_HEAD(&dev_priv->contexts.list);
-	INIT_WORK(&dev_priv->contexts.free_work, contexts_free_worker);
-	init_llist_head(&dev_priv->contexts.free_list);
-
-	/* Using the simple ida interface, the max is limited by sizeof(int) */
-	BUILD_BUG_ON(MAX_CONTEXT_HW_ID > INT_MAX);
-	BUILD_BUG_ON(GEN11_MAX_CONTEXT_HW_ID > INT_MAX);
-	ida_init(&dev_priv->contexts.hw_ida);
+	init_contexts(dev_priv);
 
 	/* lowest priority; idle task */
 	ctx = i915_gem_context_create_kernel(dev_priv, I915_PRIORITY_MIN);
@@ -487,9 +555,13 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 	}
 	/*
 	 * For easy recognisablity, we want the kernel context to be 0 and then
-	 * all user contexts will have non-zero hw_id.
+	 * all user contexts will have non-zero hw_id. Kernel contexts are
+	 * permanently pinned, so that we never suffer a stall and can
+	 * use them from any allocation context (e.g. for evicting other
+	 * contexts and from inside the shrinker).
 	 */
 	GEM_BUG_ON(ctx->hw_id);
+	GEM_BUG_ON(!atomic_read(&ctx->hw_id_pin_count));
 	dev_priv->kernel_context = ctx;
 
 	/* highest priority; preempting task */
@@ -527,6 +599,7 @@ void i915_gem_contexts_fini(struct drm_i915_private *i915)
 	destroy_kernel_context(&i915->kernel_context);
 
 	/* Must free all deferred contexts (via flush_workqueue) first */
+	GEM_BUG_ON(!list_empty(&i915->contexts.hw_id_list));
 	ida_destroy(&i915->contexts.hw_ida);
 }
 
@@ -932,6 +1005,33 @@ int i915_gem_context_reset_stats_ioctl(struct drm_device *dev,
 	return ret;
 }
 
+int __i915_gem_context_pin_hw_id(struct i915_gem_context *ctx)
+{
+	struct drm_i915_private *i915 = ctx->i915;
+	int err = 0;
+
+	mutex_lock(&i915->contexts.mutex);
+
+	GEM_BUG_ON(i915_gem_context_is_closed(ctx));
+
+	if (list_empty(&ctx->hw_id_link)) {
+		GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count));
+
+		err = assign_hw_id(i915, &ctx->hw_id);
+		if (err)
+			goto out_unlock;
+
+		list_add_tail(&ctx->hw_id_link, &i915->contexts.hw_id_list);
+	}
+
+	GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count) == ~0u);
+	atomic_inc(&ctx->hw_id_pin_count);
+
+out_unlock:
+	mutex_unlock(&i915->contexts.mutex);
+	return err;
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/mock_context.c"
 #include "selftests/i915_gem_context.c"
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index 851dad6decd7..e09673ca731d 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -134,8 +134,16 @@ struct i915_gem_context {
 	 * functions like fault reporting, PASID, scheduling. The
 	 * &drm_i915_private.context_hw_ida is used to assign a unqiue
 	 * id for the lifetime of the context.
+	 *
+	 * @hw_id_pin_count: - number of times this context had been pinned
+	 * for use (should be, at most, once per engine).
+	 *
+	 * @hw_id_link: - all contexts with an assigned id are tracked
+	 * for possible repossession.
 	 */
 	unsigned int hw_id;
+	atomic_t hw_id_pin_count;
+	struct list_head hw_id_link;
 
 	/**
 	 * @user_handle: userspace identifier
@@ -254,6 +262,21 @@ static inline void i915_gem_context_set_force_single_submission(struct i915_gem_
 	__set_bit(CONTEXT_FORCE_SINGLE_SUBMISSION, &ctx->flags);
 }
 
+int __i915_gem_context_pin_hw_id(struct i915_gem_context *ctx);
+static inline int i915_gem_context_pin_hw_id(struct i915_gem_context *ctx)
+{
+	if (atomic_inc_not_zero(&ctx->hw_id_pin_count))
+		return 0;
+
+	return __i915_gem_context_pin_hw_id(ctx);
+}
+
+static inline void i915_gem_context_unpin_hw_id(struct i915_gem_context *ctx)
+{
+	GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count) == 0u);
+	atomic_dec(&ctx->hw_id_pin_count);
+}
+
 static inline bool i915_gem_context_is_default(const struct i915_gem_context *c)
 {
 	return c->user_handle == DEFAULT_CONTEXT_HANDLE;
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index def467c2451b..9b1f0e5211a0 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1272,6 +1272,8 @@ static void execlists_context_destroy(struct intel_context *ce)
 
 static void execlists_context_unpin(struct intel_context *ce)
 {
+	i915_gem_context_unpin_hw_id(ce->gem_context);
+
 	intel_ring_unpin(ce->ring);
 
 	ce->state->obj->pin_global--;
@@ -1330,6 +1332,10 @@ __execlists_context_pin(struct intel_engine_cs *engine,
 	if (ret)
 		goto unpin_map;
 
+	ret = i915_gem_context_pin_hw_id(ctx);
+	if (ret)
+		goto unpin_ring;
+
 	intel_lr_context_descriptor_update(ctx, engine, ce);
 
 	ce->lrc_reg_state = vaddr + LRC_STATE_PN * PAGE_SIZE;
@@ -1342,6 +1348,8 @@ __execlists_context_pin(struct intel_engine_cs *engine,
 	i915_gem_context_get(ctx);
 	return ce;
 
+unpin_ring:
+	intel_ring_unpin(ce->ring);
 unpin_map:
 	i915_gem_object_unpin_map(ce->state->obj);
 unpin_vma:
diff --git a/drivers/gpu/drm/i915/selftests/mock_context.c b/drivers/gpu/drm/i915/selftests/mock_context.c
index 8904f1ce64e3..d937bdff26f9 100644
--- a/drivers/gpu/drm/i915/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/selftests/mock_context.c
@@ -43,6 +43,7 @@ mock_context(struct drm_i915_private *i915,
 
 	INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
 	INIT_LIST_HEAD(&ctx->handles_list);
+	INIT_LIST_HEAD(&ctx->hw_id_link);
 
 	for (n = 0; n < ARRAY_SIZE(ctx->__engine); n++) {
 		struct intel_context *ce = &ctx->__engine[n];
@@ -50,11 +51,9 @@ mock_context(struct drm_i915_private *i915,
 		ce->gem_context = ctx;
 	}
 
-	ret = ida_simple_get(&i915->contexts.hw_ida,
-			     0, MAX_CONTEXT_HW_ID, GFP_KERNEL);
+	ret = i915_gem_context_pin_hw_id(ctx);
 	if (ret < 0)
 		goto err_handles;
-	ctx->hw_id = ret;
 
 	if (name) {
 		ctx->name = kstrdup(name, GFP_KERNEL);
@@ -85,11 +84,7 @@ void mock_context_close(struct i915_gem_context *ctx)
 
 void mock_init_contexts(struct drm_i915_private *i915)
 {
-	INIT_LIST_HEAD(&i915->contexts.list);
-	ida_init(&i915->contexts.hw_ida);
-
-	INIT_WORK(&i915->contexts.free_work, contexts_free_worker);
-	init_llist_head(&i915->contexts.free_list);
+	init_contexts(i915);
 }
 
 struct i915_gem_context *
-- 
2.19.0.rc1

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^ permalink raw reply related	[flat|nested] 28+ messages in thread

end of thread, other threads:[~2018-09-04 22:02 UTC | newest]

Thread overview: 28+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-08-16 21:07 [PATCH 01/23] drm/i915: Cache the error string Chris Wilson
2018-08-16 21:07 ` [PATCH 02/23] drm/i915/execlists: Avoid kicking priority on the current context Chris Wilson
2018-08-16 21:07 ` [PATCH 03/23] drm/i915: Missed interrupt simulation is no more, tell the world Chris Wilson
2018-08-16 21:07 ` [PATCH 04/23] drm/i915/selftests: Basic stress test for rapid context switching Chris Wilson
2018-08-16 21:07 ` [PATCH 05/23] drm/i915/execlists: Delay updating ring register state after resume Chris Wilson
2018-08-16 21:07 ` [PATCH 06/23] drm/i915/execlists: Use coherent writes into the context image Chris Wilson
2018-08-16 21:07 ` [PATCH 07/23] drm/i915/execlists: Onion unwind for logical_ring_init() failure Chris Wilson
2018-08-16 21:07 ` [PATCH 08/23] drm/i915: Report the number of closed vma held by each context in debugfs Chris Wilson
2018-08-16 21:07 ` [PATCH 09/23] drm/i915: Remove debugfs/i915_ppgtt_info Chris Wilson
2018-08-16 21:07 ` [PATCH 10/23] drm/i915/execlists: Assert the queue is non-empty on unsubmitting Chris Wilson
2018-08-16 21:07 ` [PATCH 11/23] drm/i915/execlists: Reset queue_priority on cancellation Chris Wilson
2018-08-16 21:07 ` [PATCH 12/23] drm/i915/execlists: Include reset depth in traces Chris Wilson
2018-08-16 21:07 ` [PATCH 13/23] drm/i915/execlists: Use direct submission to restart HW after reset Chris Wilson
2018-08-16 21:07 ` [PATCH 14/23] drm/i915: Attach the pci match data to the device upon creation Chris Wilson
2018-08-16 21:07 ` [PATCH 15/23] drm/i915: Track all held rpm wakerefs Chris Wilson
2018-08-16 21:07 ` [PATCH 16/23] drm/i915: Markup paired operations on wakerefs Chris Wilson
2018-08-16 21:07 ` [PATCH 17/23] drm/i915: Syntatic sugar for using intel_runtime_pm Chris Wilson
2018-08-16 21:07 ` [PATCH 18/23] drm/i915: Markup paired operations on display power domains Chris Wilson
2018-08-16 21:07 ` [PATCH 19/23] drm/i915: Track the wakeref used to initialise " Chris Wilson
2018-08-16 21:07 ` [PATCH 20/23] drm/i915/dp: Markup pps lock power well Chris Wilson
2018-08-16 21:07 ` [PATCH 21/23] drm/i915: Complain if hsw_get_pipe_config acquires the same power well twice Chris Wilson
2018-08-16 21:07 ` [PATCH 22/23] drm/i915: Mark up Ironlake ips with rpm wakerefs Chris Wilson
2018-08-16 21:07 ` [PATCH 23/23] drm/i915: Enable runtime-pm debugging by default for CI Chris Wilson
2018-08-16 21:43 ` ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/23] drm/i915: Cache the error string Patchwork
2018-08-16 21:50 ` ✗ Fi.CI.SPARSE: " Patchwork
2018-08-16 21:59 ` ✓ Fi.CI.BAT: success " Patchwork
2018-08-17  2:36 ` ✓ Fi.CI.IGT: " Patchwork
  -- strict thread matches above, loose matches on Subject: below --
2018-09-04 21:57 [PATCH 01/23] drm/i915: Reduce context HW ID lifetime Chris Wilson
2018-09-04 21:57 ` [PATCH 02/23] drm/i915/execlists: Avoid kicking priority on the current context Chris Wilson

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